基于PTO转矩估计的液压机械无级变速装载机速比控制策略

doi:10.3901/JME.2024.18.362

摘要/Abstract

摘要： 为了解决液压机械无级变速装载机作业过程中工作装置阻力多变导致作业效率和经济性下降的问题，基于液压机械功率流特性分析，提出取力器轴(Power take-off，PTO)转矩估计方法，并制定基于PTO转矩估计的速比调节策略。以搭载液压机械无级变速器的ZL50型装载机为研究对象，分析液压机械效率、转矩及功率流特性，以液压回路压差及发动机转速、转矩等关键参量为输入建立PTO转矩估计模型；分析PTO转矩对目标速比的影响，提出考虑PTO转矩的目标速比求解方法并制定速比控制策略；以典型作业循环阻力和行驶里程为参考构建V型循环工况，在Matlab/Simulink中搭建液压机械装载机仿真平台，开展控制策略的仿真验证。结果表明，除换段等瞬态工况，估计转矩最大误差为9.18%，平均误差3.78%，可将该估计结果用于策略的制定；与传统控制策略相比，基于PTO转矩制定的速比控制策略在PTO需求转矩较小时，速比变大，车速提升，发动机负荷率提高；PTO需求转矩变大时，速比减小，功率更多分配至作业系统，有效提高作业效率和燃油经济性；完成一个V型循环工作效率提高6.29%，经济性提高3.95%。

关键词: 装载机, 液压机械无级传动, 取力器, 转矩估计, 速比调节

Abstract: Hydro-mechanical continuously variable transmission(HMT) has become one of the development directions of wheel loader transmission system, because of its ability to achieve high-power stepless speed changing and high-efficiency transmission. However, the resistance of the working device changes frequently during the operation, which will reduce the working efficiency and economy. To solve this problems, a ZL50 type wheel loader equipped with HMT is taken as the research object. The characteristics of HMT’s efficiency, torque and power flow are analyzed, and a Power take-off(PTO) torque estimation model is established with the key parameters such as hydraulic circuit pressure, engine speed, torque, etc. The influence of PTO torque on the target speed ratio is analyzed, a method to solve the target speed ratio considering PTO torque is proposed, and the speed ratio control strategy is formulated. In order to verify the effectiveness of this strategy, the V-type working cycle is constructed with reference to the typical operation cycle resistance and distance, and the simulation platform of the loader equipped with HMT is built in Matlab/Simulink. The results show that, the maximum error of the torque estimation is 9.18% except for transient conditions such as range changing; Compared with the traditional control strategy, the speed ratio control strategy based on PTO torque can increase the speed ratio, vehicle speed and engine load rate when the PTO demand torque is small; when the PTO torque demand becomes larger, it can reduce the speed ratio, distribute more power to the working system; the work efficiency is increased by 6.29% and the total fuel consumption is saved by 3.95% in a V-type working cycle.

Key words: loader, hydro-mechanical continuously variable transmission, power take-off, torque estimation, speed ratio adjustment

中图分类号:

U463

杨树军, 史正旭, 彭增雄, 李学良, 褚捷豪. 基于PTO转矩估计的液压机械无级变速装载机速比控制策略[J]. 机械工程学报, 2024, 60(18): 362-373.

YANG Shujun, SHI Zhengxu, PENG Zengxiong, LI Xueliang, CHU Jiehao. Speed Ratio Control Strategy of Wheel Loader with HMT Based on PTO Torque Estimation[J]. Journal of Mechanical Engineering, 2024, 60(18): 362-373.

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